Learning human languages other than English is not only a major career asset, it opens the door to cross-cultural understanding, boosts self-esteem and expands horizons in so many ways.

Sadly, in the nation’s most diverse and global city, home to the United Nations, the benefits that come with learning a foreign language are being acquired by far too few public school students.

The era of intense focus on (and standardized testing in) math and English has taken a heavy toll on foreign language instruction in New York City. Our young people learn in schools where foreign languages have been pushed to the margins.

Only about 5% of our elementary school students receive regular instruction in world languages. Most young people don’t take their first course in another language until high school. And increasingly critical non-European languages are rarely taught.

The city’s Department of Education has no senior leader focused exclusively on world languages, and no goals for principals or for the system as a whole for achievement in this area.

We know what works in foreign language instruction: early learning and immersion. Young minds absorb new languages with ease, including the ability to achieve native-speaker fluency. This facility is lost once children pass puberty.

But even at an early age, fluency can only truly be attained through immersion. An hour a week of language instruction can help children acquire basic vocabulary or learn select phrases or songs — but not much more.

Cutting-edge schools around the globe, and here, smartly teach children general content (social studies, math, etc.) in a foreign language for several periods a day. The State of Utah has reoriented its entire school system around this immersion strategy.

New York City has a series of a dual-language programs, in both private and public schools, that offer a glimpse of the potential of early immersion here. In some, native English speakers and English-language learners spend half of their days in classes taught in English, and half in classes taught in a foreign language.

Schools Chancellor Carmen Fariña, who has said she wants every New York City student to speak at least two languages, significantly expanded the number of dual-language programs this year. But in total, these programs still reach only about 2% of elementary school students — and virtually none continue into middle and high school.

New York City needs to set ambitious but achievable goals for its young people to attain the language skills critical for success in the 21st century.

Every family who wants it should have the option of a foreign language immersion track for their children. And every student not on that track should get at least two periods per week of foreign language instruction, beginning in kindergarten. Yes, kindergarten.

We should expand our offerings in the languages most demanded by employers, including non-Western European languages like Mandarin, Arabic, Russian and Japanese.

To achieve these ambitious goals, we will need to ramp up recruitment of foreign language teachers. We must revise the certification rules to ease entry of new teachers, including those from abroad. And we need to ensure that every foreign language teacher has access to high-quality professional development.

Only through bold action can New York City succeed in preparing our children to compete for jobs in a polyglot world.

Levine represents upper Manhattan and Dromm represents parts of Queens in the New York City Council.